# How does acetic acid behave as an acid in water?

In aqueous solution, acetic acid is $\text{monoprotic............}$
${H}_{3} C - C {O}_{2} H \left(a q\right) + {H}_{2} O \left(l\right) \rightarrow {H}_{3} C - C {O}_{2}^{-} + {H}_{3} {O}^{+}$
Of course, the equilibrium lies strongly to the left. From memory, ${K}_{a} = {10}^{- 4.76}$.